鲕状赤铁矿氢气低温还原焙烧机理探讨

Mechanism for Hydrogen Reduction of Oolitic Hematite at Low Temperature

考察了氢气气氛下还原时间、还原温度和还原度等对鲕状赤铁矿还原过程的影响。通过电感耦合等离子原子发射光谱仪(ICP-AES)、光学显微镜、X射线衍射仪(XRD)等表征手段对还原焙烧矿物及其磁选后精矿进行了表征。结果表明:随着氢气还原时间增加,鲕状赤铁矿还原度逐步增大,还原焙烧矿金属化率逐步增大。400℃下,高纯氢气还原90 min,所得焙烧矿经磁选后可获得精矿铁品位55.55%、回收率76.94%的指标。氢气低温还原赤铁矿还原过程为:Fe_2O_3→Fe_3O_4→Fe_3O_4-δ→FeO→Fe_3O_4+Fe→Fe,但从宏观看产物由Fe_3O_4直接变为Fe,中间没有FeO产生。

The reduction of oofitic hematite with H2 under the effect of several factors, such as temperature, hofding time and degree of reduction, was investigated. The minerals after reduction roasting process and concentrate from magnetic separation process were analyzed by ICP- AES, optical microscope and X-ray diffraction （ XRD）. Results indicated that with the increasing of reduction time,the degree of reduction of oofitic hematite increased gradually and the metalized ratio of ore after reduction roasting process also gradually increased. After being roasted at 400 ^ for 90 min with H2,the obtained roasted ore was subjected to magnetic separation process, resulting in the concentrate around 55.55% Fe grade at 76.94% recovery. The mechanism for low-temperature reduction-roasting of oofitic hematite with H2 is as foflows： Fe2O3→Fe3O4→Fe3O4-δ→FeO→Fe3O4＋Fe→Fe. In summary, the product was directly transferred from Fe3O4 into Fe,without the intermediate product of FeO.